1. Field of the Invention
The invention relates to a temperture limiter with a rod-like temperature sensor, which operates at least one switch.
2. Prior Art
Such temperature limiters, which in general terms can be used as temperature switches, are particularly used where electrically heated equipment, such as electric hotplates, radiant heaters of glass ceramic cooking units, baking oven muffles and the like have to be protected against overheating. DE-OS 34 23 086 (U.S. Pat. No. 4,544,831) discloses a corresponding temperature limiter for regulating or limiting the temperature of radiant or contact heater bodies of electrical cookers insulating material tube is kept constantly under compressive stress by a compression spring acting on a rod within the base, because the outer end of the inner rod which is tensile-loaded by the spring, acts on the outer end of the insulating tube. The insulating tube is relatively brittle and therefore easily breakable, which on the one hand makes it difficult to introduce the compressive forces into its ends and on the other hand also leads to strength problems between the ends, because the insulating tube is bending-stressed. Thus, in this construction once again a relatively large diameter of the insulating tube is to be sought and in order to bring about a uniform introduction of the compressive forces there are end caps mounted on its ends, which leads to a very complicated construction and relatively large cross-sections. As the temperature sensor, e.g. when placed on radiant heaters, produces back-radiation or reflection, which increases with increasing temperature sensor diameter, in the case of the known construction there can be local overheating of the heating resistors as a result of this back-radiation. Admittedly the requirement of a relatively small diameter is usually met in the case of temperature sensors with a metallic outer tube, but the electrical conductivity of said outer tube is disadvantageous in many applications, so that on the metallic outer tube it is necessary to place a protective insulating tube, which leads to a very complicated construction and to an increase in the temperature sensor diameter.